According to MPEG-H 3D Audio, various types of signals can be processed and the type of an input/output can be easily controlled. Thus, MPEG-H 3D Audio may function as a solution for next-generation audio signal processing. In addition, according to trends toward miniaturization of apparatuses, the percentage of audio reproduction via a mobile device in a stereo reproduction environment has increased.
When an immersive audio signal realized via multiple channels, such as 22.2 channels, is delivered to a stereo reproducing system, all input channels should be decoded, and the immersive audio signal should be downmixed to be converted into a stereo format.
As the number of input channels is increased and the number of output channels is decreased, the complexity of a decoder necessary for a covariance analysis and a phase alignment increases during the process described above. This increase in complexity affects not only an operation speed of mobile devices but also battery consumption of mobile devices.